Electrical indicating instrument



' 1929- P. GELATT ELECTRICAL INDICATING' INSTRUMENT Filed Aug 24, 1925 Patented Aug. 6, 1929 UNITED STATES:

PATENT OFFICE.

PHILO u. GELATT, or LA cnossE, wrsconsm, Assmlwon, BY MESNE ASSIGNMENTS, 'ro N TIONAL GAUGE a EQUIPMENT eourANY, or WILMINGTON, DELAWARE, A

CORPORATION OF DELAWARE. i

ELECTRICAL I NDIC ATING INSTRUMENT.

Application filed August '24, 1825. Serial No. 52,190.

automobile use wherein the indicator 1 preferably .located at some distance fl'OIDi the tank. The improvement relates particularly to that type of improved electri asoline indicator illustrated in Letters\ .atent N 0. 1,522,355 issued to B. F Winterdescribed AS indicated in Fig 1 the in g hoif January 6, 1925, and the improvement member or any other suitable means in the mannerfully shown and described in the said Winterhofi patent. 2 indicates a source of electrical supply shown for illustrative purposes only as the battery in the present case and 4 indicates the electromagnetically-operated instrument containing the improvement hereinafter more fully is particularly directed to overcoming detrument 4 is placed in circuit with the batfects in that type of indicator, due to the fact that when the generator charges the battery there is caused thereby a mater al variation in the voltage of the current that ry and rheostat through the wires 3 and 3 that the indicator of the instrument 4 will be responsive'to movement of the arm '0 the rheostat and themarking of the dial passes through the coil of the volt meter, is so arranged as to indicate the amount of and consequently the instrument, properly calibrated for the. primary current developed by the battery, will not be properly calibrated for the change in current brought about b the generator chargmgthe battery. his improvement is' designed to compensate for those proportional variations in the voltage of the different currents developed by the battery and by the generator, and this improvement 1s so arranged in its relation to the standard equipment of an automobile that it will automatically compensate for the increased voltage of the current developed by the generator and will not be affected by the varying voltages resulting from charged conditions no rmall occurring in the usual type of circuit su c as the generator being cut in or out or the battery being discharged to a. material extent.

Fig. 1 is a diagrammatic view'showrng the ordinary type of rheostat in circuit with the battery and voltmeten Fig. 2 is a section taken on the line of Fig. 3 with the cap and dial removed to permita view of the parts secured wltlll ll the instrument. i

Fig. 3 is a transverse sectional vlew.

Fig. 4 is a sectional .view .on the line 44 of Fig. 3.

Fig. 5 is a cross sectional view on 55 of Fig. 2. Like parts are indicated by like figures of reference throughout the different views.

Referring to F ig. l-of the drawings, 1 indicates the rheostat which is of the ordinary type illustrated in said Letters Patent to \Vinterhofi No. 1,522,355 and the arm of this rheostat may be connected to a float the line gasoline in the tank by the position of. the indicator 5 in'its relatlon to the dial of the instrument 4, this being fully described in the Letters Patent aforesaid.

This improvement concerns itself with theconstruction of the instrument 4 and its arrangement whereby an accurate indication by the instrument will be maintained 7 whether the-current is one developed by the battery or the generator. The general type of instrument is one that is well known and consists of a permanent magnet 6 with attenuated pole pieces 7 and the magnet 6 and pole pieces 7 are secured to the casing of the instrument in the usual and ordinary way a as best illustrated in the reissue patent to Axen No. 14,733. The permanent magnet is preferably made of steel and of such magnetic design that it'is notentirely saturated with the permanent magnetism.

There is the usual coil 8 the terminals of-which are secured to the posts 9 and this coil is connected in the usual and ordinary way so that the indicator 5 of the instrument will indicate the amount of current passing through the coil. The indicating pointer 5 is secured upon the shaft 10 which in turn is secured in bearings in the usual and ordinary way as fully described in said Axen patent and indicated in Fig. 5. This indicator shaft 10 carries an armature 11 and this armature lies below and in close proxiniity to the ends of the attenuated pole pieces 'I. The coil 8 is wound about metal holders 12 (see Fig. 3) and these metal pieces aresecured to fibrous members 13. In this specific form of coil arrangement illustrated herein there is a space between the companion plates 12, and one end of the armature 11 its oscillations will enter within said space.

The permanent magnet 6 is shown partially surrounded by a coil of wire 13 and this coil has terminals 14 and 14 which are .connected' to the" generator Gr through the wires 16 and 17, w1th.t he circuit preferably controlled by the switch .S which may be of any general type sueh 'asthe ordinary cutout or. relay switch, as indicated in Fig. 1, whereby the coil is put; in series with the generator. The coil "13 is also connected in series with the battery 2 thru the respective connections 14, 18 and 14, 19.

The leads from the generator for charging thebattery are shown diagrammatically 16, 18, and .17, 19," the result being that when the generator charges the battery the magnet will be correspondingly excited to compensate for this. change in voltage of the current generated by the generator and to also compensate in general for any variations of voltage at the source such as a low battery. Consequently the strength of the magnet will always fluctuate to compensate for the proportional increases in voltage and the instrument 4 will. indicate properly under all conditions. By reason of the fact that the magnet 6 is not P rmanently satu-v rated by magnetism, the current passing through the coil 13 will increase the magnetic field of said magnet.

As indicated in Figs. 3 and 5., the instrument 4 is arrangedto be attached tothe cowl or" an automobile or any similar part so that this instrumentd can be placed atture pivoted in the fields ofsaid magnet and as thru Wires I coil, saidmagnet' and coil being adapted to act on said armature in opposition, one to the other, and anauxihary series cell for increasing the effect of'said permanent mag.-

net in accordance with an increase involtage, of the charging current. 7

2.111, a dilferential. galvanometer of the character described the combination of an armature, a permanent magnet for deter-- mining the initial position of said armature,

a main coil forming an clectro-magnct adapted to act on said armature in opposition tosaid permanent magnet, and-an aux- .iliary coil around said permanent magnet and a charging member connected in the circuit in a manner to increase the effect of said permanent magnet and to thereby compensate for variations of voltage due to the charging member.

- 3. In an indicating instrument of the character described, a pivoted armature, a permanentmagnet for establishing theinitial position of said armature, a 'main coil adapted to be connected in a circuit to be measured for influencing the position of the armature in accordance with the variations to be measured, and an auxiliary coil-and generator adapted to be connected in the circuit, the current therein varying in accordance with variations of voltage, of the generator and arranged to supply amagneticfield acting in the same direction as said permanent magnet, to compensate for variations in voltage due to said generator.

4. In an indicating instrnment of the character described, a first coiladapted to be connected in a variable current circuit to be measured, a permanent magnet, an armature pivoted in the fields ofboth said mag-v net and coil and acted on thereby in-opposite directions, and a second coil and a generator adapted to be connected directly to the same and arranged to strengthen the field of the permanent magnet in accordance with any increase in voltage at said generator thereby compensating for variations in said voltage.

In testimony whereof, I have hereunto set my hand this 18th day of August 1925.

PHILO M. GELATT. 

